This new export type exposes to userspace the SRAM area as a DMA-BUF Heap, this allows for allocations of DMA-BUFs that can be consumed by various DMA-BUF supporting devices.
Signed-off-by: Andrew Davis afd@ti.com ---
Changes from v2: - Make sram_dma_heap_allocate static (kernel test robot) - Rebase on v6.5-rc1
drivers/misc/Kconfig | 7 + drivers/misc/Makefile | 1 + drivers/misc/sram-dma-heap.c | 245 +++++++++++++++++++++++++++++++++++ drivers/misc/sram.c | 6 + drivers/misc/sram.h | 16 +++ 5 files changed, 275 insertions(+) create mode 100644 drivers/misc/sram-dma-heap.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 75e427f124b28..ee34dfb61605f 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -448,6 +448,13 @@ config SRAM config SRAM_EXEC bool
+config SRAM_DMA_HEAP + bool "Export on-chip SRAM pools using DMA-Heaps" + depends on DMABUF_HEAPS && SRAM + help + This driver allows the export of on-chip SRAM marked as both pool + and exportable to userspace using the DMA-Heaps interface. + config DW_XDATA_PCIE depends on PCI tristate "Synopsys DesignWare xData PCIe driver" diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index f2a4d1ff65d46..5e7516bfaa8de 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -47,6 +47,7 @@ obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o obj-$(CONFIG_SRAM) += sram.o obj-$(CONFIG_SRAM_EXEC) += sram-exec.o +obj-$(CONFIG_SRAM_DMA_HEAP) += sram-dma-heap.o obj-$(CONFIG_GENWQE) += genwqe/ obj-$(CONFIG_ECHO) += echo/ obj-$(CONFIG_CXL_BASE) += cxl/ diff --git a/drivers/misc/sram-dma-heap.c b/drivers/misc/sram-dma-heap.c new file mode 100644 index 0000000000000..c054c04dff33e --- /dev/null +++ b/drivers/misc/sram-dma-heap.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * SRAM DMA-Heap userspace exporter + * + * Copyright (C) 2019-2022 Texas Instruments Incorporated - https://www.ti.com/ + * Andrew Davis afd@ti.com + */ + +#include <linux/dma-mapping.h> +#include <linux/err.h> +#include <linux/genalloc.h> +#include <linux/io.h> +#include <linux/mm.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include <linux/dma-buf.h> +#include <linux/dma-heap.h> + +#include "sram.h" + +struct sram_dma_heap { + struct dma_heap *heap; + struct gen_pool *pool; +}; + +struct sram_dma_heap_buffer { + struct gen_pool *pool; + struct list_head attachments; + struct mutex attachments_lock; + unsigned long len; + void *vaddr; + phys_addr_t paddr; +}; + +struct dma_heap_attachment { + struct device *dev; + struct sg_table *table; + struct list_head list; +}; + +static int dma_heap_attach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + struct dma_heap_attachment *a; + struct sg_table *table; + + a = kzalloc(sizeof(*a), GFP_KERNEL); + if (!a) + return -ENOMEM; + + table = kmalloc(sizeof(*table), GFP_KERNEL); + if (!table) { + kfree(a); + return -ENOMEM; + } + if (sg_alloc_table(table, 1, GFP_KERNEL)) { + kfree(table); + kfree(a); + return -ENOMEM; + } + sg_set_page(table->sgl, pfn_to_page(PFN_DOWN(buffer->paddr)), buffer->len, 0); + + a->table = table; + a->dev = attachment->dev; + INIT_LIST_HEAD(&a->list); + + attachment->priv = a; + + mutex_lock(&buffer->attachments_lock); + list_add(&a->list, &buffer->attachments); + mutex_unlock(&buffer->attachments_lock); + + return 0; +} + +static void dma_heap_detatch(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + struct dma_heap_attachment *a = attachment->priv; + + mutex_lock(&buffer->attachments_lock); + list_del(&a->list); + mutex_unlock(&buffer->attachments_lock); + + sg_free_table(a->table); + kfree(a->table); + kfree(a); +} + +static struct sg_table *dma_heap_map_dma_buf(struct dma_buf_attachment *attachment, + enum dma_data_direction direction) +{ + struct dma_heap_attachment *a = attachment->priv; + struct sg_table *table = a->table; + + /* + * As this heap is backed by uncached SRAM memory we do not need to + * perform any sync operations on the buffer before allowing device + * domain access. For this reason we use SKIP_CPU_SYNC and also do + * not use or provide begin/end_cpu_access() dma-buf functions. + */ + if (!dma_map_sg_attrs(attachment->dev, table->sgl, table->nents, + direction, DMA_ATTR_SKIP_CPU_SYNC)) + return ERR_PTR(-ENOMEM); + + return table; +} + +static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, + struct sg_table *table, + enum dma_data_direction direction) +{ + dma_unmap_sg_attrs(attachment->dev, table->sgl, table->nents, + direction, DMA_ATTR_SKIP_CPU_SYNC); +} + +static void dma_heap_dma_buf_release(struct dma_buf *dmabuf) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + + gen_pool_free(buffer->pool, (unsigned long)buffer->vaddr, buffer->len); + kfree(buffer); +} + +static int dma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + int ret; + + /* SRAM mappings are not cached */ + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); + + ret = vm_iomap_memory(vma, buffer->paddr, buffer->len); + if (ret) + pr_err("Could not map buffer to userspace\n"); + + return ret; +} + +static int dma_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + + iosys_map_set_vaddr(map, buffer->vaddr); + + return 0; +} + +static const struct dma_buf_ops sram_dma_heap_buf_ops = { + .attach = dma_heap_attach, + .detach = dma_heap_detatch, + .map_dma_buf = dma_heap_map_dma_buf, + .unmap_dma_buf = dma_heap_unmap_dma_buf, + .release = dma_heap_dma_buf_release, + .mmap = dma_heap_mmap, + .vmap = dma_heap_vmap, +}; + +static struct dma_buf *sram_dma_heap_allocate(struct dma_heap *heap, + unsigned long len, + unsigned long fd_flags, + unsigned long heap_flags) +{ + struct sram_dma_heap *sram_dma_heap = dma_heap_get_drvdata(heap); + struct sram_dma_heap_buffer *buffer; + + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct dma_buf *dmabuf; + int ret = 0; + + buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); + if (!buffer) + return ERR_PTR(-ENOMEM); + buffer->pool = sram_dma_heap->pool; + INIT_LIST_HEAD(&buffer->attachments); + mutex_init(&buffer->attachments_lock); + buffer->len = len; + + buffer->vaddr = (void *)gen_pool_alloc(buffer->pool, buffer->len); + if (!buffer->vaddr) { + ret = -ENOMEM; + goto free_buffer; + } + + buffer->paddr = gen_pool_virt_to_phys(buffer->pool, (unsigned long)buffer->vaddr); + if (buffer->paddr == -1) { + ret = -ENOMEM; + goto free_pool; + } + + /* create the dmabuf */ + exp_info.exp_name = dma_heap_get_name(heap); + exp_info.ops = &sram_dma_heap_buf_ops; + exp_info.size = buffer->len; + exp_info.flags = fd_flags; + exp_info.priv = buffer; + dmabuf = dma_buf_export(&exp_info); + if (IS_ERR(dmabuf)) { + ret = PTR_ERR(dmabuf); + goto free_pool; + } + + return dmabuf; + +free_pool: + gen_pool_free(buffer->pool, (unsigned long)buffer->vaddr, buffer->len); +free_buffer: + kfree(buffer); + + return ERR_PTR(ret); +} + +static struct dma_heap_ops sram_dma_heap_ops = { + .allocate = sram_dma_heap_allocate, +}; + +int sram_add_dma_heap(struct sram_dev *sram, + struct sram_reserve *block, + phys_addr_t start, + struct sram_partition *part) +{ + struct sram_dma_heap *sram_dma_heap; + struct dma_heap_export_info exp_info; + + dev_info(sram->dev, "Exporting SRAM Heap '%s'\n", block->label); + + sram_dma_heap = kzalloc(sizeof(*sram_dma_heap), GFP_KERNEL); + if (!sram_dma_heap) + return -ENOMEM; + sram_dma_heap->pool = part->pool; + + exp_info.name = kasprintf(GFP_KERNEL, "sram_%s", block->label); + exp_info.ops = &sram_dma_heap_ops; + exp_info.priv = sram_dma_heap; + sram_dma_heap->heap = dma_heap_add(&exp_info); + if (IS_ERR(sram_dma_heap->heap)) { + int ret = PTR_ERR(sram_dma_heap->heap); + kfree(sram_dma_heap); + return ret; + } + + return 0; +} diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c index 5757adf418b1d..6dd173a2fba8e 100644 --- a/drivers/misc/sram.c +++ b/drivers/misc/sram.c @@ -120,6 +120,12 @@ static int sram_add_partition(struct sram_dev *sram, struct sram_reserve *block, ret = sram_add_pool(sram, block, start, part); if (ret) return ret; + + if (block->export) { + ret = sram_add_dma_heap(sram, block, start, part); + if (ret) + return ret; + } } if (block->export) { ret = sram_add_export(sram, block, start, part); diff --git a/drivers/misc/sram.h b/drivers/misc/sram.h index 397205b8bf6ff..062bdd25fa068 100644 --- a/drivers/misc/sram.h +++ b/drivers/misc/sram.h @@ -60,4 +60,20 @@ static inline int sram_add_protect_exec(struct sram_partition *part) return -ENODEV; } #endif /* CONFIG_SRAM_EXEC */ + +#ifdef CONFIG_SRAM_DMA_HEAP +int sram_add_dma_heap(struct sram_dev *sram, + struct sram_reserve *block, + phys_addr_t start, + struct sram_partition *part); +#else +static inline int sram_add_dma_heap(struct sram_dev *sram, + struct sram_reserve *block, + phys_addr_t start, + struct sram_partition *part) +{ + return 0; +} +#endif /* CONFIG_SRAM_DMA_HEAP */ + #endif /* __SRAM_H */
On Thu, Jul 13, 2023 at 02:13:16PM -0500, Andrew Davis wrote:
+int sram_add_dma_heap(struct sram_dev *sram,
struct sram_reserve *block,phys_addr_t start,struct sram_partition *part)+{
- struct sram_dma_heap *sram_dma_heap;
- struct dma_heap_export_info exp_info;
- dev_info(sram->dev, "Exporting SRAM Heap '%s'\n", block->label);
When drivers are working properly, they are quiet.
thanks,
greg k-h
On 7/13/23 2:27 PM, Greg Kroah-Hartman wrote:
On Thu, Jul 13, 2023 at 02:13:16PM -0500, Andrew Davis wrote:
+int sram_add_dma_heap(struct sram_dev *sram,
struct sram_reserve *block,phys_addr_t start,struct sram_partition *part)+{
- struct sram_dma_heap *sram_dma_heap;
- struct dma_heap_export_info exp_info;
- dev_info(sram->dev, "Exporting SRAM Heap '%s'\n", block->label);
When drivers are working properly, they are quiet.
This should only be printed once in early boot when the memory is added, I was wanting this to match the other memory exporters/output at the beginning of boot logs.
But quiet is fine too, will change this to dev_dbg() for v4.
Thanks, Andrew
thanks,
greg k-h
On Thu, Jul 13, 2023 at 02:13:16PM -0500, Andrew Davis wrote:
This new export type exposes to userspace the SRAM area as a DMA-BUF Heap, this allows for allocations of DMA-BUFs that can be consumed by various DMA-BUF supporting devices.
What devices exactly?
And what userspace tools/programs are going to use this api?
Signed-off-by: Andrew Davis afd@ti.com
Changes from v2:
- Make sram_dma_heap_allocate static (kernel test robot)
- Rebase on v6.5-rc1
drivers/misc/Kconfig | 7 + drivers/misc/Makefile | 1 + drivers/misc/sram-dma-heap.c | 245 +++++++++++++++++++++++++++++++++++ drivers/misc/sram.c | 6 + drivers/misc/sram.h | 16 +++ 5 files changed, 275 insertions(+) create mode 100644 drivers/misc/sram-dma-heap.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 75e427f124b28..ee34dfb61605f 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -448,6 +448,13 @@ config SRAM config SRAM_EXEC bool +config SRAM_DMA_HEAP
- bool "Export on-chip SRAM pools using DMA-Heaps"
- depends on DMABUF_HEAPS && SRAM
- help
This driver allows the export of on-chip SRAM marked as both pooland exportable to userspace using the DMA-Heaps interface.
Module name?
config DW_XDATA_PCIE depends on PCI tristate "Synopsys DesignWare xData PCIe driver" diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index f2a4d1ff65d46..5e7516bfaa8de 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -47,6 +47,7 @@ obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o obj-$(CONFIG_SRAM) += sram.o obj-$(CONFIG_SRAM_EXEC) += sram-exec.o +obj-$(CONFIG_SRAM_DMA_HEAP) += sram-dma-heap.o obj-$(CONFIG_GENWQE) += genwqe/ obj-$(CONFIG_ECHO) += echo/ obj-$(CONFIG_CXL_BASE) += cxl/ diff --git a/drivers/misc/sram-dma-heap.c b/drivers/misc/sram-dma-heap.c new file mode 100644 index 0000000000000..c054c04dff33e --- /dev/null +++ b/drivers/misc/sram-dma-heap.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- SRAM DMA-Heap userspace exporter
- Copyright (C) 2019-2022 Texas Instruments Incorporated - https://www.ti.com/
- Andrew Davis afd@ti.com
It's 2023 :(
And this needs review from the dma-buf maintainers before I could do anything with it.
thanks,
greg k-h
Am 13.07.23 um 21:28 schrieb Greg Kroah-Hartman:
On Thu, Jul 13, 2023 at 02:13:16PM -0500, Andrew Davis wrote:
This new export type exposes to userspace the SRAM area as a DMA-BUF Heap, this allows for allocations of DMA-BUFs that can be consumed by various DMA-BUF supporting devices.
What devices exactly?
And what userspace tools/programs are going to use this api?
Signed-off-by: Andrew Davis afd@ti.com
Changes from v2:
- Make sram_dma_heap_allocate static (kernel test robot)
- Rebase on v6.5-rc1
drivers/misc/Kconfig | 7 + drivers/misc/Makefile | 1 + drivers/misc/sram-dma-heap.c | 245 +++++++++++++++++++++++++++++++++++ drivers/misc/sram.c | 6 + drivers/misc/sram.h | 16 +++ 5 files changed, 275 insertions(+) create mode 100644 drivers/misc/sram-dma-heap.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 75e427f124b28..ee34dfb61605f 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -448,6 +448,13 @@ config SRAM config SRAM_EXEC bool +config SRAM_DMA_HEAP
- bool "Export on-chip SRAM pools using DMA-Heaps"
- depends on DMABUF_HEAPS && SRAM
- help
This driver allows the export of on-chip SRAM marked as both pooland exportable to userspace using the DMA-Heaps interface.Module name?
config DW_XDATA_PCIE depends on PCI tristate "Synopsys DesignWare xData PCIe driver" diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index f2a4d1ff65d46..5e7516bfaa8de 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -47,6 +47,7 @@ obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o obj-$(CONFIG_SRAM) += sram.o obj-$(CONFIG_SRAM_EXEC) += sram-exec.o +obj-$(CONFIG_SRAM_DMA_HEAP) += sram-dma-heap.o obj-$(CONFIG_GENWQE) += genwqe/ obj-$(CONFIG_ECHO) += echo/ obj-$(CONFIG_CXL_BASE) += cxl/ diff --git a/drivers/misc/sram-dma-heap.c b/drivers/misc/sram-dma-heap.c new file mode 100644 index 0000000000000..c054c04dff33e --- /dev/null +++ b/drivers/misc/sram-dma-heap.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- SRAM DMA-Heap userspace exporter
- Copyright (C) 2019-2022 Texas Instruments Incorporated - https://www.ti.com/
- Andrew Davis afd@ti.com
It's 2023 :(
And this needs review from the dma-buf maintainers before I could do anything with it.
Yeah, agree. Thanks Greg.
It would be nice if you explicitly CC the maintainers for DMA-buf and DMA-buf heaps as well.
Of hand I can only find the version from 2020 in the LKML archives.
Regards, Christian.
thanks,
greg k-h _______________________________________________ Linaro-mm-sig mailing list -- linaro-mm-sig@lists.linaro.org To unsubscribe send an email to linaro-mm-sig-leave@lists.linaro.org
On 2023-07-13 20:13, Andrew Davis wrote:
This new export type exposes to userspace the SRAM area as a DMA-BUF Heap, this allows for allocations of DMA-BUFs that can be consumed by various DMA-BUF supporting devices.
Signed-off-by: Andrew Davis afd@ti.com
Changes from v2:
- Make sram_dma_heap_allocate static (kernel test robot)
- Rebase on v6.5-rc1
drivers/misc/Kconfig | 7 + drivers/misc/Makefile | 1 + drivers/misc/sram-dma-heap.c | 245 +++++++++++++++++++++++++++++++++++ drivers/misc/sram.c | 6 + drivers/misc/sram.h | 16 +++ 5 files changed, 275 insertions(+) create mode 100644 drivers/misc/sram-dma-heap.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 75e427f124b28..ee34dfb61605f 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -448,6 +448,13 @@ config SRAM config SRAM_EXEC bool +config SRAM_DMA_HEAP
- bool "Export on-chip SRAM pools using DMA-Heaps"
- depends on DMABUF_HEAPS && SRAM
- help
This driver allows the export of on-chip SRAM marked as both pooland exportable to userspace using the DMA-Heaps interface.- config DW_XDATA_PCIE depends on PCI tristate "Synopsys DesignWare xData PCIe driver"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index f2a4d1ff65d46..5e7516bfaa8de 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -47,6 +47,7 @@ obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o obj-$(CONFIG_SRAM) += sram.o obj-$(CONFIG_SRAM_EXEC) += sram-exec.o +obj-$(CONFIG_SRAM_DMA_HEAP) += sram-dma-heap.o obj-$(CONFIG_GENWQE) += genwqe/ obj-$(CONFIG_ECHO) += echo/ obj-$(CONFIG_CXL_BASE) += cxl/ diff --git a/drivers/misc/sram-dma-heap.c b/drivers/misc/sram-dma-heap.c new file mode 100644 index 0000000000000..c054c04dff33e --- /dev/null +++ b/drivers/misc/sram-dma-heap.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- SRAM DMA-Heap userspace exporter
- Copyright (C) 2019-2022 Texas Instruments Incorporated - https://www.ti.com/
- Andrew Davis afd@ti.com
- */
+#include <linux/dma-mapping.h> +#include <linux/err.h> +#include <linux/genalloc.h> +#include <linux/io.h> +#include <linux/mm.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include <linux/dma-buf.h> +#include <linux/dma-heap.h>
+#include "sram.h"
+struct sram_dma_heap {
- struct dma_heap *heap;
- struct gen_pool *pool;
+};
+struct sram_dma_heap_buffer {
- struct gen_pool *pool;
- struct list_head attachments;
- struct mutex attachments_lock;
- unsigned long len;
- void *vaddr;
- phys_addr_t paddr;
+};
+struct dma_heap_attachment {
- struct device *dev;
- struct sg_table *table;
- struct list_head list;
+};
+static int dma_heap_attach(struct dma_buf *dmabuf,
struct dma_buf_attachment *attachment)+{
- struct sram_dma_heap_buffer *buffer = dmabuf->priv;
- struct dma_heap_attachment *a;
- struct sg_table *table;
- a = kzalloc(sizeof(*a), GFP_KERNEL);
- if (!a)
return -ENOMEM;- table = kmalloc(sizeof(*table), GFP_KERNEL);
- if (!table) {
kfree(a);return -ENOMEM;- }
- if (sg_alloc_table(table, 1, GFP_KERNEL)) {
kfree(table);kfree(a);return -ENOMEM;- }
- sg_set_page(table->sgl, pfn_to_page(PFN_DOWN(buffer->paddr)), buffer->len, 0);
What happens if someone (reasonably) assumes that this struct page pointer isn't completely made up, and dereferences it?
(That's if pfn_to_page() itself doesn't blow up, which it potentially might, at least under CONFIG_SPARSEMEM)
I think this needs to be treated as P2PDMA if it's going to have any hope of working robustly.
- a->table = table;
- a->dev = attachment->dev;
- INIT_LIST_HEAD(&a->list);
- attachment->priv = a;
- mutex_lock(&buffer->attachments_lock);
- list_add(&a->list, &buffer->attachments);
- mutex_unlock(&buffer->attachments_lock);
- return 0;
+}
+static void dma_heap_detatch(struct dma_buf *dmabuf,
struct dma_buf_attachment *attachment)+{
- struct sram_dma_heap_buffer *buffer = dmabuf->priv;
- struct dma_heap_attachment *a = attachment->priv;
- mutex_lock(&buffer->attachments_lock);
- list_del(&a->list);
- mutex_unlock(&buffer->attachments_lock);
- sg_free_table(a->table);
- kfree(a->table);
- kfree(a);
+}
+static struct sg_table *dma_heap_map_dma_buf(struct dma_buf_attachment *attachment,
enum dma_data_direction direction)+{
- struct dma_heap_attachment *a = attachment->priv;
- struct sg_table *table = a->table;
- /*
* As this heap is backed by uncached SRAM memory we do not need to* perform any sync operations on the buffer before allowing device* domain access. For this reason we use SKIP_CPU_SYNC and also do* not use or provide begin/end_cpu_access() dma-buf functions.*/
I bet that works really well with SWIOTLB ;)
Also note that SKIP_CPU_SYNC is only a hint, so the DMA API implementation is still at liberty to do the fatally dangerous things you're hoping it won't (e.g. dereferencing sg_virt()...)
Thanks, Robin.
- if (!dma_map_sg_attrs(attachment->dev, table->sgl, table->nents,
direction, DMA_ATTR_SKIP_CPU_SYNC))return ERR_PTR(-ENOMEM);- return table;
+}
+static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
struct sg_table *table,enum dma_data_direction direction)+{
- dma_unmap_sg_attrs(attachment->dev, table->sgl, table->nents,
direction, DMA_ATTR_SKIP_CPU_SYNC);+}
+static void dma_heap_dma_buf_release(struct dma_buf *dmabuf) +{
- struct sram_dma_heap_buffer *buffer = dmabuf->priv;
- gen_pool_free(buffer->pool, (unsigned long)buffer->vaddr, buffer->len);
- kfree(buffer);
+}
+static int dma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) +{
- struct sram_dma_heap_buffer *buffer = dmabuf->priv;
- int ret;
- /* SRAM mappings are not cached */
- vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
- ret = vm_iomap_memory(vma, buffer->paddr, buffer->len);
- if (ret)
pr_err("Could not map buffer to userspace\n");- return ret;
+}
+static int dma_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map) +{
- struct sram_dma_heap_buffer *buffer = dmabuf->priv;
- iosys_map_set_vaddr(map, buffer->vaddr);
- return 0;
+}
+static const struct dma_buf_ops sram_dma_heap_buf_ops = {
- .attach = dma_heap_attach,
- .detach = dma_heap_detatch,
- .map_dma_buf = dma_heap_map_dma_buf,
- .unmap_dma_buf = dma_heap_unmap_dma_buf,
- .release = dma_heap_dma_buf_release,
- .mmap = dma_heap_mmap,
- .vmap = dma_heap_vmap,
+};
+static struct dma_buf *sram_dma_heap_allocate(struct dma_heap *heap,
unsigned long len,unsigned long fd_flags,unsigned long heap_flags)+{
- struct sram_dma_heap *sram_dma_heap = dma_heap_get_drvdata(heap);
- struct sram_dma_heap_buffer *buffer;
- DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
- struct dma_buf *dmabuf;
- int ret = 0;
- buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
- if (!buffer)
return ERR_PTR(-ENOMEM);- buffer->pool = sram_dma_heap->pool;
- INIT_LIST_HEAD(&buffer->attachments);
- mutex_init(&buffer->attachments_lock);
- buffer->len = len;
- buffer->vaddr = (void *)gen_pool_alloc(buffer->pool, buffer->len);
- if (!buffer->vaddr) {
ret = -ENOMEM;goto free_buffer;- }
- buffer->paddr = gen_pool_virt_to_phys(buffer->pool, (unsigned long)buffer->vaddr);
- if (buffer->paddr == -1) {
ret = -ENOMEM;goto free_pool;- }
- /* create the dmabuf */
- exp_info.exp_name = dma_heap_get_name(heap);
- exp_info.ops = &sram_dma_heap_buf_ops;
- exp_info.size = buffer->len;
- exp_info.flags = fd_flags;
- exp_info.priv = buffer;
- dmabuf = dma_buf_export(&exp_info);
- if (IS_ERR(dmabuf)) {
ret = PTR_ERR(dmabuf);goto free_pool;- }
- return dmabuf;
+free_pool:
- gen_pool_free(buffer->pool, (unsigned long)buffer->vaddr, buffer->len);
+free_buffer:
- kfree(buffer);
- return ERR_PTR(ret);
+}
+static struct dma_heap_ops sram_dma_heap_ops = {
- .allocate = sram_dma_heap_allocate,
+};
+int sram_add_dma_heap(struct sram_dev *sram,
struct sram_reserve *block,phys_addr_t start,struct sram_partition *part)+{
- struct sram_dma_heap *sram_dma_heap;
- struct dma_heap_export_info exp_info;
- dev_info(sram->dev, "Exporting SRAM Heap '%s'\n", block->label);
- sram_dma_heap = kzalloc(sizeof(*sram_dma_heap), GFP_KERNEL);
- if (!sram_dma_heap)
return -ENOMEM;- sram_dma_heap->pool = part->pool;
- exp_info.name = kasprintf(GFP_KERNEL, "sram_%s", block->label);
- exp_info.ops = &sram_dma_heap_ops;
- exp_info.priv = sram_dma_heap;
- sram_dma_heap->heap = dma_heap_add(&exp_info);
- if (IS_ERR(sram_dma_heap->heap)) {
int ret = PTR_ERR(sram_dma_heap->heap);kfree(sram_dma_heap);return ret;- }
- return 0;
+} diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c index 5757adf418b1d..6dd173a2fba8e 100644 --- a/drivers/misc/sram.c +++ b/drivers/misc/sram.c @@ -120,6 +120,12 @@ static int sram_add_partition(struct sram_dev *sram, struct sram_reserve *block, ret = sram_add_pool(sram, block, start, part); if (ret) return ret;
if (block->export) {ret = sram_add_dma_heap(sram, block, start, part);if (ret)return ret;}diff --git a/drivers/misc/sram.h b/drivers/misc/sram.h index 397205b8bf6ff..062bdd25fa068 100644 --- a/drivers/misc/sram.h +++ b/drivers/misc/sram.h @@ -60,4 +60,20 @@ static inline int sram_add_protect_exec(struct sram_partition *part) return -ENODEV; } #endif /* CONFIG_SRAM_EXEC */
+#ifdef CONFIG_SRAM_DMA_HEAP +int sram_add_dma_heap(struct sram_dev *sram,
struct sram_reserve *block,phys_addr_t start,struct sram_partition *part);+#else +static inline int sram_add_dma_heap(struct sram_dev *sram,
struct sram_reserve *block,phys_addr_t start,struct sram_partition *part)+{
- return 0;
+} +#endif /* CONFIG_SRAM_DMA_HEAP */
- #endif /* __SRAM_H */
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